Abstract: The real-time response characteristics of drilling tools contain important engineering geological information. By interpreting the drilling data, the rock mass integrity can be quantitatively evaluated, which provides a new way to quickly obtain the geological characteristics of engineering rock mass. A new type of digital geological drilling monitoring system is established by using the high-precision digital hydraulic, torque, rotational speed and laser displacement sensors to monitor the transmission part of geological drill. Based on the real-time, continuous and synchronous drilling response characteristic parameters of drilling tools, the functional relationships among drilling thrust, rotational torque, rotational speed and drilling rate are established. On this basis, the influences of drilling machine parameters on drilling rate are filtered out, and a new index, drilling process index, is proposed to express the rock mass integrity. The digital change of the drilling process index can comprehensively reflect the fragmentation degree of rock mass, and the rock mass integrity can be obtained through the information method and data operation. The complicated procedures such as statistical work of RQD and drillingcore sketch are reduced, and the adverse influences of human subjective factors are also reduced.